The use of broadband wireless networks, such as third-generation (3G) and fourth generation (4G) mobile broadband networks, continues to expand. Users of these wireless networks can move to different locations (communication cells) in a coverage area and maintain network connectivity. These networks are typically configured having base stations with a certain wireless communication range to define a coverage area. The base stations may be connected to a wired network using, for example, a high-speed network connection such as fiber optics, T1, DSL, cable modem, etc. The communication path in these wireless networks is typically from (i) a mobile user to a base station across the wireless link and (ii) from the base station to the network (e.g., wide area network (WAN)) using a wired or high bandwidth wireless (e.g., microwave) connection. Thus, a mobile device (e.g., cellular telephone or land mobile radio) communicates with the network via one or more wireless base stations.
As the communication rates of these wireless networks increases, such as in the 4G networks, higher communication capacity is provided resulting in lower cell footprints. Accordingly, a large number of cells (e.g., picocells) are needed, each of which needs a backhaul connection. When employing a half duplex frequency division duplex (HFDD) mode in wireless networks, self-backhauling of the cell may be provided using the same protocol and frequencies. Also, the radio units for HFDD wireless networks are simpler to design because the units do not have to transmit and receive at the same time. However, a loss of communication capacity and communication throughput in the network results because bi-directional communication can only be provided in one direction at a time and not simultaneously (as in full-duplex communications). Accordingly, half of the communication capacity is lost.
One exemplary HFDD system is set forth in U.S. Patent Publication No. 2009/0207762. This reference discloses a method for assigning mobile users in a half-frequency division duplex (HFDD) system to a first UL group and second UL group of an uplink (UL) sub-frame, and to a first DL group and a second DL group of a downlink (DL) sub-frame. The UL sub-frame is assigned a first carrier frequency and the DL sub-frame is assigned a second carrier frequency. The method includes determining a type of data, determining a receive CINR (carrier interference plus noise ratio), and determining a Doppler frequency parameter, for each mobile user of a plurality of mobile users. The plurality of mobile users are assigned to the first UL group and/or the second UL group time durations of the first and second UL groups, and based on at least one of the data type, CINR, Doppler frequency spread of the mobile user, and a number of mobile users previously assigned to the first and second UL groups.